Fix stats_fetch_consistency default value indicated in postgresql.conf.sample.
Mistake in
5891c7a8ed8, likely made when switching the default value from none
to fetch during development.
Reported-By: Nathan Bossart <nathandbossart@gmail.com>
Author: Nathan Bossart <nathandbossart@gmail.com>
Discussion: https://postgr.es/m/
20220524220147.GA1298892@nathanxps13